We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
This makes the wrapper more like the rest in LibCore, and also
removes the annoying limitation of not supporting arguments.
There are three overloads one for String, char const *, and StringView
argument lists. As long as there are <= 10 arguments the argv list
will be allocated inline, otherwise on the heap.
This is a simple wrapper around posix_spawn() that will help us simplify
a bunch of very verbose posix_spawn() invocations.
This first version only supports the simplest case: executing an
executable without passing arguments or doing anything fancy. More
features can be added to cover more cases. :^)
